#include <iostream>
#include <string>
#include <sstream>
#include <algorithm>
using namespace std;

const int maxv = 10000 + 10;
int in_order[maxv],post_order[maxv],lch[maxv],rch[maxv];
int n;
int best, best_sum;

bool read_list(int * p){
	string s;
	if(!getline(cin,s)) return false;
	stringstream ss(s);
	n = 0;
	int x = 0;
	while(ss >> x){
		p[n++] = x;
	}
	return n > 0;
}

//return root of the tree, building the tree
int build(int L1,int R1,int L2,int R2)
{
	if(L1 > R1) return 0;
	int root = post_order[R2];
	int p = L1;
	while(in_order[p] != root) p++;
	int cnt = p - L1;//the number of left child tree`s node
	lch[root] = build(L1, p-1, L2, L2+cnt-1);
	rch[root] = build(p+1, R1, L2+cnt, R2-1);
	return root;
}

void dfs(int u, int sum)
{
	sum += u;
	if(!lch[u] && !rch[u]){
		if(sum < best_sum || (sum == best_sum && u < best)){ best = u; best_sum = sum;}
	}
	if(lch[u]) dfs(lch[u],sum);
	if(rch[u]) dfs(rch[u],sum);
}

int main()
{
	while(read_list(in_order)){
		read_list(post_order);
		build(0,n-1,0,n-1);
		best_sum = 1000000;
		dfs(post_order[n-1],0);
		cout << best << "\n";
	}
	return 0;
}
